Electronic structures of ${\mathrm{C}}_{\mathrm{60}}$ and its endohedral complexes with Li, Na, K, Be, Mg, Ca, La, B, and Al have been calculated by means of density functional methodology. The electronic distributions have been analyzed from the point of view of the guest-host electron transfer. Alkali metals and Al have been found to donate their outermost electron to the fullerene cage. There is no electron transfer for Be, while for B, Mg, Ca, and La the transfer is only partial. For the entire series, ionization potentials and electron affinities have been calculated which are in excellent agreement with the few values known from experiments. The results are consistent with the donor-acceptor properties of the guest atom.

The location of Cu cations in CuZSM-5, properties of cationic sites and their interaction with guest molecules have been studied by quantum chemical (DFT) modeling and IR spectroscopy based on the frequency shift of antisymmetric T–O–T vibration of oxygen rings. The shift has been found sensitive both to the framework interaction with cations and to the interaction with adsorbed molecules. It has been measured and estimated theoretically from parameters characterising framework distorsion by Cu⁺ and Cu²⁺, with MgZSM-5 and NaZSM-5 used as ‘‘reference samples’’. It was found that the ordering of the cation perturbing effect was: Na⁺<Cu⁺<Mg²⁺<Cu²⁺. NO interaction with Cu cations was much stronger than that of CO and N₂ . Divalent copper showed polarized 2-electron covalent bonding with NO strengthening its bond while moderate bonding ability of monovalent copper led to NO bond activation, in accordance with high catalytic activity of Cu⁺ZSM-5.